Determinedly protecting Steven Gerrard’s early penalty, Liverpool had six defenders on the pitch by the end of this Carling Cup semi-final first leg, doggedly refusing to yield an inch as they edged closer to a first visit to Wembley in 16 years.

Liverpool’s hunger was unmistakeable, suffusing the way they snapped into tackles, closing down anyone in a blue shirt. They attacked briskly for an hour before retreating so deep that their lone striker Andy Carroll was almost in a separate post-code.

For the last half-hour, Kenny Dalglish kept strengthening the barricades. Liverpool didn’t so much shut up shop as board up the windows, nail crooked planks across the back-door and lay sandbags around the 18-yard box.

By the end, Liverpool had a back five of Glen Johnson, Martin Kelly, Martin Skrtel, Daniel Agger and Jose Enrique shielded by Jamie Carragher. Jordan Henderson, Gerrard and Charlie Adam patrolled as sentries just in front of them and they almost needed binoculars to spot the distant Carroll.

For Liverpool, the end justified the cautious means. They took an away goal and a clean sheet back to Anfield for the Jan 25 second leg. They took a step towards the Feb 26 final at Wembley. Their fans, who briefly broke into “attack, attack, attack” in the second half, soon realised Dalglish’s intent and admired their resolve.

For City, there was only frustration. As hard as Sergio Agüero ran, City badly missed the locksmith skills of David Silva in attempting to break through. They missed Yaya Touré’s powerful surges through the middle.

Mario Balotelli limped off in the first half, having injured his ankle, and his replacement Samir Nasri lacked the energy to trouble Liverpool. Edin Dzeko came on but also failed to impose himself.

Among the few City players emerging with reputations enhanced were Joe Hart, exceptional in the first half, and Micah Richards, who kept charging upfield while never neglecting his defensive duties.

Fabio Capello may not rate him but Richards wins more admirers by the week. City’s annoyance spilled into anger when a rival to the England right-back spot, Glen Johnson, launched himself into a challenge on Joleon Lescott that echoed Vincent Kompany’s on Nani in the FA Cup on Sunday.

The cameras zoomed in on the banned Kompany, kicking his heels in an executive box.

On a day when English referees were being honoured by Fifa, with Michael Oliver rising to the Fifa list and Mark Clattenburg joining Howard Webb and Martin Atkinson in the elite category, the debate over refereeing consistency continued. Johnson escaped without censure.

Kompany has to sit out four games. The sooner referees issue a short post-match statement clarifying any talking points the better.

Lee Mason hardly needed to be Perry Mason to detect the infringement that gifted Liverpool their spot-kick. Stefan Savic, an under-par understudy for Kompany, was already struggling, soon erring badly in challenging Agger, clearly fouling him. Mason pointed to the spot, and Gerrard did the rest, ignoring the green laser pen shining on his face to slide the penalty low to Hart’s right.

Hart had been at his defiant best until then. City were heavily indebted to their agile England international to keep Liverpool at bay as a red storm tore their way. Hart quickly made three good saves, diving out to deny Carroll, pushing away a Gerrard shot and then a deflected Stewart Downing volley. The last save was special, Hart dropping to his left and stretching out a hand to thwart Downing.

Liverpool kept pouring forward, taking the lead through Gerrard, who continued to set their high tempo. They even took the loss of Jay Spearing in their stride, the midfielder feeling his hamstring tighten and being replaced by Adam.

The Scot’s first involvement was a delight, a beautiful 40-yard pass driven from the centre to Craig Bellamy on the right. It was still unfortunate for Spearing, who had just returned from suspension and had been looking promising in the Lucas role.

Balotelli was going through the enigma variations, mainly off key though. Fouled by Adam, the Italian reacted furiously, particularly when the Liverpool midfielder tapped him on the head. James Milner stepped in smartly to steer Balotelli away. The striker demanded the ball for the free-kick which he then drove angrily into the Liverpool wall.

Balotelli soon went off, Nasri trotted on, tested Pepe Reina, but again failed to command the City fans’ affections.

Trying to change his players’ mood and the direction of the game, Roberto Mancini changed his formation, going three at the back with Gaël Clichy pushed far down the left, the Frenchman whipping in some good crosses.

City were far better after the break, moving the ball quicker. When Martin Kelly played the ball back blind to Reina, Agüero pounced, nicking the ball and moving to go round the Liverpool keeper.

City kept hunting that equaliser. Milner slotted the ball wide to Nasri, who curled in a terrific cross that Reina reached just before Gareth Barry. City hammered away. Barry drove a low cross in from the right which Agger thumped out for a corner.

It was far from pretty. Nasri, who seemed the aggressor, and Carragher were both cautioned for a coming together of heads. As tempers rose, the level of football fell further. Gerrard booted the ball clear.

Mancini frantically ran down the line to get a loose ball. Johnson then jumped into that tackle on Lescott. A penny for Kompany’s thoughts. How City missed their leader as well as Yaya Touré and Silva.

Mancini’s men have much work to do at Anfield if they are to turn this tie around. Advantage Liverpool.